1630s, present participle adjective from abound; originally "affluent;" sense of "overflowing" is recorded by 1680s.

abound

v.

early 14c., from Old French abonder "to abound, be abundant, come together in great numbers" (12c.), from Latin abundare "overflow, run over," from Latin ab- "off" (see ab-) + undare "rise in a wave," from unda "water, wave" (see water (n.)). Related: Abounded; abounding.